Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!haven!umbc3!rostamia
From: rostamia@umbc3.UMBC.EDU (Rouben Rostamian)
Newsgroups: comp.unix.questions
Subject: Bourne Shell: Variable defined?
Keywords: Bourne shell, elementary question
Message-ID: <1819@umbc3.UMBC.EDU>
Date: 21 Mar 89 03:03:08 GMT
Organization: Univ of Maryland Baltimore County
Lines: 13

In C Shell the variable $?foo returns true or false (0 of 1, really)
depending on whether or not the variable "foo" has been already defined.
What is the equivalent construction in Bourne Shell?  In other words,
how can I tell, in Bourne Shell, whether the variable "foo" exits.

Sorry if the question is too elementary;  I am new to unix.


-- 
Rouben Rostamian
Department of Mathematics                      e-mail:
University of Maryland Baltimore Counnty       Rostamian@umbc2.bitnet
Baltimore, MD 21228                            rostamia@umbc3.umbc.edu